More than 100 foreign nationals have been blacklisted from Indonesia's electoral roll after the country's General Election Commission (KPU) found they were erroneously enrolled to cast ballots in 17 provinces across the archipelago.

Key points

Some Indonesians have been paid up to $25 in exchange for their votes

The KPU found almost 3 million duplicate names ahead of the April elections

It's estimated about 1.6 million indigenous voters could be excluded from voting

The announcement comes after a Chinese national was found on the electoral roll in the place of an Indonesian citizen due to an input error by the election commission.

Some supporters of Opposition Leader Prabowo Subianto, who has frequently accused incumbent President Joko "Jokowi" Widodo of being too close to Beijing, seized on the case of the Chinese national to argue there were elements of electoral fraud taking place.

Incidents like these arejust one of the problems likely to plague the upcoming Indonesian general election, where more than 187 million eligible voters in the world's third-largest democracy will choose both their president and members of parliament on April 17.

It also highlightstheongoing struggle to tackle misinformation and hoaxes amid what many observers see as a period of democratic stagnation.

In January, a hoax spread via WhatsApp and Twitter that there were shipping containers full of pre-filled voter cards from China, all for Jokowi, sitting at Jakarta's port.

Some media reports alleged Chinese and Russian hackers sought to disrupt the electoral process, but Indonesia's election commission denied those state-actors were the behind the hacking attempts.

It is tough competition for the up to 8,000 candidates who will fight for 575 seats in the House of Representatives and the tens of thousands who are running for the 19,817 seats on the provincial, regency, and city level legislative councils — but researchers are already warning that ongoing vote buying presents a major hurdle to democracy in the country.

Professor Edward Aspinall from the Australian National University told the ABC that many voters in Indonesia cast their vote based on much more immediate considerations, such as money to fulfil their needs.

"A large degree of voting in Indonesia is organised around direct exchange of material benefits for votes," Professor Aspinall said.

For example, a member of a mainstream nationalist partyon Borneo island, West Kalimantan, told the ABC he was responsible for distributing vote-buying payments during local elections in 2014.

Johannes, not his real name, said voters were paid Rp 250,000 ($25) each in exchange for their votes.

"The strategy had been effective," he said.

'Democracy for sale': Vote buying a democracy killer

Professor Aspinall said practices such as vote buying, influence peddling and skimming money from government projects were rife across the archipelago, and dubbed it as "democracy for sale" for his forthcoming book.

He also said vote buying was more prevalent and effective in islands outside of Java, where economic power is much more concentrated.

"A lot of the vote buying happens at the parliamentary elections, much less so for presidential elections, partly because the scale of the presidential election is much greater," he said.

"[But] now they're happening at the same time, so there's going to be a lot more overlap."

Professor Aspinall found while payments for votes were likely to be higher for local elections, it was not effective for capturing votes if there was also social pressure from influential religious, cultural or government figures in the community.

A separate research project by Burhanuddin Muhtadi, a lecturer at Universitas Islam Negeri Syarif Hidayatullah Jakarta, found that during elections in the period between 2006 and 2016, roughly a third of 800,000 respondents said they had been given cash or other items in exchange for votes.

Millions of 'ghost votes' popping up across the nation

In Indonesia, all citizens over the age of 17 are required to hold an e-KTP (electronic identity card) in order to vote.

But the e-KTP scheme itself had been marred by a corruption scandal in which senior politicians embezzled some Rp 2.3 trillion ($227 million), with former parliamentary speaker Setya Novanto given a sentence of 15 years for his role in stealing taxpayer money.

As a result, millions of Indonesians are yet to receive their cards.

The Alliance of Indigenous Peoples of the Archipelago (AMAN) said that until late 2018, roughly 1.6 million indigenous Indonesians might have been excluded from voting in the April election because they did not have an e-KTP.